From: Robert Richter <rric@kernel.org>
To: Josh Boyer <jwboyer@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@ghostprotocols.net>,
x86@kernel.org, linux-kernel@vger.kernel.org, gleb@redhat.com
Subject: Re: Drop WARN on AMD lack of perfctrs
Date: Fri, 17 May 2013 00:33:45 +0200 [thread overview]
Message-ID: <20130516223345.GF8356@rric.localhost> (raw)
In-Reply-To: <20130516215459.GD18325@hansolo.jdub.homelinux.org>
On 16.05.13 17:54:59, Josh Boyer wrote:
> On Thu, May 16, 2013 at 10:55:58PM +0200, Robert Richter wrote:
> > On 16.05.13 20:10:18, Peter Zijlstra wrote:
> > > I would make it a FW_BUG as well. But yeah, I suppose that is a better option
> > > than the WARN_ON. Unless Robert had a different reason...
> >
> > iirc the reason was the different msr range that is switched on fam15h
> > with a different counter to counter msr offset of 2 instead of 1. The
> > code relies on the assumption that the msrs exist on that cpu. Thus
> > the warning if not. Also note that code may have changed in 3.10 in
> > that area.
>
> Again, what is someone supposed to do with a backtrace from the WARN?
> As far as I can see, a user can't really do anything other than report
> it and then there's nothing to fix.
>
> The code might have moved in 3.10, but the WARN is still there.
>
> Would you like me to send a patch to get it reduced to pr_err?
I wrote the code with the assumption of a certain system layout which
was the check for. Now, in a vm this assumption is no longer valid.
Will change the code in a way this is handled properly.
-Robert
next prev parent reply other threads:[~2013-05-16 22:33 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-16 15:10 Drop WARN on AMD lack of perfctrs Josh Boyer
2013-05-16 17:51 ` Peter Zijlstra
2013-05-16 17:55 ` Josh Boyer
2013-05-16 18:10 ` Peter Zijlstra
2013-05-16 20:55 ` Robert Richter
2013-05-16 21:34 ` Borislav Petkov
2013-05-17 9:04 ` Peter Zijlstra
2013-05-17 9:16 ` Borislav Petkov
2013-05-17 9:27 ` Peter Zijlstra
2013-05-17 9:45 ` Borislav Petkov
2013-05-17 10:36 ` Robert Richter
2013-05-17 10:57 ` Peter Zijlstra
2013-05-21 8:56 ` Robert Richter
2013-05-21 11:05 ` Peter Zijlstra
2013-05-21 13:58 ` Robert Richter
2013-05-21 15:20 ` Jacob Shin
2013-05-28 13:03 ` [tip:perf/core] perf/x86/amd: Rework AMD PMU init code tip-bot for Peter Zijlstra
2013-05-16 21:54 ` Drop WARN on AMD lack of perfctrs Josh Boyer
2013-05-16 22:33 ` Robert Richter [this message]
2013-05-16 19:31 ` Gleb Natapov
2013-05-16 20:00 ` Borislav Petkov
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